MOTORIZED SURGICAL INSTRUMENT
FIELD OF THE INVENTION
The present disclosure relates in general to surgical instrument that augments surgeon's ability to
perform minimally invasive procedures, and more particularly to advanced surgical instruments
capable of exhibiting enhanced surgical performance with independent control of motion during the
surgical procedure.
Furthermore, the disclosure relates to surgical instrument having replaceable tool tips facilitate
substituting a more appropriate tool tip for a "previous one" for performing a different function or
similar function more precisely.
BACKGROUND OF THE INVENTION
Minimally invasive surgical procedure has successfully replaced conventional surgery by making it
less traumatic with significantly reduced incision size through which the surgical instrument is
inserted. In existing robot-assisted surgical procedures, the surgical instrument driving unit is usually
mounted on the manipulating robotic arm to rotate the instrument about the instrument axis and end
effectors about the pivotal connection which offers disadvantages that may hamper the progress of
minimally invasive surgery.
The currently prevailing minimally invasive surgical technology is therefore constrained in its
applicability as it involves an assembly of colossal manipulating means to effectuate articulation of
the surgical instrument at the surgical site. Since the motion of the surgical instrument is driven by
driving units mounted on the manipulating robotic arms, the surgical instrument is configured to
adapt itself only to manipulators accommodating such complementing arrangements of driving unit.
There is a limitation to the configurations possible with only this configuration, of which limited
dexterity and minimal mobility are the most formidable challenges cited by the surgeons. The
surgical instrument, thus, is not rendered independently functional, meaning the given configuration
requires accompanying set up to achieve basic functionality thereby limiting functionality. Further,
there has been always a need to establish mechanical and electrical connections to transmit physical
motion to the surgical instrument, thus requiring arduous disassembly and reassembly procedures.
Moreover, in In robotic surgical field, the surgical instruments that are mounted to perform the
surgery are usually disposed off after one single use, or are repeatedly sterilized after each single
use. As acknowledged by those skilled in the art that the tips of these surgical instruments, primarily
forceps or gripper that remains attached to the distal end of the surgical instrument for performing
the surgery get degraded by the use of plurality of times thereby providing a possibility that
malfunction occurs in use by this degradation.
In view of aforementioned limitations what is needed therefore is a surgical instrument enabling
precise control over the end effectors through the use of control drive elements of the instrument that
can make the instrument get employed with different manipulating medical arms used in the industry
today; hence simplifying the control arrangement with consequent cost savings. Also, needed is a
surgical instrument that allows easy replacement of surgical instrument tips which may facilitate
easy sterilization process thereby further cutting exorbitant cost involved in replacing the entire
surgical instrument after few surgical use.
The foregoing discussion is intended only to illustrate some of the shortcomings present in the field
of the invention at the time, and should not be taken as a disavowal of claim scope.
SUMMARY OF THE INVENTION
In connection with the general aspects of various embodiments of the present invention, there is
provided a surgical instrument that at least in one form, comprises a longitudinal shaft having shaft
axis defining a proximal end and a distal end, said shaft configured to be rotatable about the shaft
axis in response to the actuation motion thereto. The elongated shaft operably couples to a wrist
member at its distal end by a pivotal connection defining a wrist axis. The wrist member is
configured to be angularly displaceable about the wrist axis by atleast two wrist member-moving
actuators that are operatively coupled to a single continuous wrist member-moving elongate element
such that selective pulling of one end of the elongate element causes concomitant movement of the
wrist member therewith in one direction while counter-pulling causes movement of the wrist
member in opposed other direction.
Further, towards the working end of the wrist member is provided a pair of working members: a first
working member and a second working member coupled by a common pivotal connection to wrist
member to define working member axis, and the working members being configured to be displaced
angularly about the working member axis when independently actuated by first working membermoving
actuator coupled with corresponding first working member-moving elongate element or
second working member-moving actuator coupled with corresponding second working membermoving
elongate element respectively.
In connection with yet another general aspect of one form of the present invention, the shaft rotating
actuators, wrist member-moving actuators and the working member-moving actuators are sterlizable,
and are configured to generate a plurality of discrete motions of the shaft, the wrist member and the
working members upon application of actuation motions thereto.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are incorporated in and constitute a part of this specification,
illustrate embodiments of the invention, and, together with the general description of the invention
given above, and the detailed description of the embodiments given below, serve to explain the
principles of the various forms of the present invention.
Figure 1 is an exploded perspective view of one form of surgical instrument in accordance with an
embodiment of the present invention.
Figure 2 is an exploded perspective view of wrist member of the surgical instrument in accordance
with an embodiment of the present invention.
Figure 3 is view illustrating functional aspects of the wrist member and the working members in
accordance with and embodiment of the present invention.
Figure 4 is a simplified perspective drawing showing the carriage plate with various guiding
mechanisms in accordance with an embodiment of the present invention.
Figure 5 illustrates one other view of the carriage plate coupled to the elongated shaft in accordance
with an embodiment of the present invention.
Figure 6 illustrates another perspective view of the carriage plate with elongate members laid over
the guiding mechanisms in accordance with an embodiment of the present invention.
Figure 7 illustrates placement of wrist member moving actuators in accordance with an embodiment
of the present invention.
Figure 8 is a top view of the carriage plate housing actuators and a gear assembly in accordance with
one embodiment of the present invention.
Figure 9 is a perspective illustration of robotic surgical instrument having replaceable working
members, in accordance with one embodiment of the present invention.
Figure 10 is an exploded view of robotic surgical instrument having replaceable working members,
in accordance with one embodiment of the present invention.
Figure 11 illustrates yet another embodiment of robotic surgical instrument having replaceable
working members.
DETAILED DESCRIPTION OF THE INVENTION
Certain exemplary embodiments will now be described to provide an overall understanding of the
principles of the structure, function, manufacture, and use of the devices and methods disclosed
herein. One or more examples of these embodiments are illustrated in the accompanying drawings.
Those of ordinary skill in the art will understand that the devices and methods specifically described
herein and illustrated in the accompanying drawings are non-limiting exemplary embodiments and
that the scope of the various embodiments of the present invention is defined solely by the claims.
The features illustrated or described in connection with one exemplary embodiment may be
combined with the features of other embodiments. Such modifications and variations are intended to
be included within the scope of the present invention.
Reference throughout the specification to "various embodiments," "some embodiments," "one
embodiment," or "an embodiment", or the like, means that a particular feature, structure, or
characteristic described in connection with the embodiment is included in at least one embodiment.
Thus, appearances of the phrases "in various embodiments," "in some embodiments," "in one
embodiment", or "in an embodiment", or the like, in places throughout the specification are not
necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or
characteristics may be combined in any suitable manner in one or more embodiments. Thus, the
particular features, structures, or characteristics illustrated or described in connection with one
embodiment may be combined, in whole or in part, with the features structures, or characteristics of
one or more other embodiments without limitation. Such modifications and variations are intended
to be included within the scope of the present invention.
The terms "proximal" and "distal" are used herein with reference to a patient-side assistant
manipulating the casing portion or carriage plate end of the surgical instrument. The term
"proximal" referring to the portion closest to the patient side assistant and the term "distal" referring
to the portion located away from the assistant and towards the patient. It will be further appreciated
that, for convenience and clarity, spatial terms such as "vertical", "horizontal", "up", and "down"
may be used herein with respect to the drawings. However, surgical instruments are used in many
orientations and positions, and these terms are not intended to be limiting and/or absolute.
In one further aspect of the invention, the surgical instrument is releasably secured to the robotic arm
using any suitable releasable attachment means or interface. Thus unlike, in standard roboticallyassisted
surgery wherein the operational position of surgical instrument is controlled by a drive
assembly enclosed within the housing of robotic arm and requires proportional coordinated
movements between the surgical instrument and the articulated arm; the present disclosure is
particularly useful for controlling the surgical instruments at the surgical site independent of the
relative proportional movements of the entire robotic arm. This is achieved by involving surgical
instrument of modular construction, as will be explained later.
Reference is now made to Figure 1 wherein one form of a surgical instrument 100, in accordance
with first preferred embodiment of the present invention is illustrated. In at least one embodiment,
the surgical instrument 100 includes a carriage plate assembly 20 that is attached to an elongated
shaft assembly 10 that is configured for operable attachment to a variety of different surgical tool
heads or working members 40(a) and 40(b).
Figure 1 illustrates an exploded view of the surgical instrument 100 comprising a wrist member
assembly 30 coupled towards its working end with different working members 40(a) and 40(b), the
attachment and operation of which will be discussed in further detail below. In the depicted
embodiment, the carriage plate assembly 20 operably supports an actuation system generally
designated as 25 which is configured to selectively apply various forms of actuation motions to the
particular-type of working members, commonly designated as 40, attached thereto. As the present
detailed description proceeds, those of ordinary skill in the art will appreciate that surgical
instrument 100 disclosed herein may be configured to operably interface with a robotic control
system that can provide the requisite control signals to actuate actuating system 25 present within the
instrument 100.
In the given embodiment, all practical motions of surgical instrument 100, namely the rotational
movement of the instrument about its axis, rotation of the wrist member 30, and opening and closing
action of the working members 40 or their rotation independent of each other, are power
implemented by the instrument's actuators and gear assembly housed in its carriage plate 20.
It is to be understood that further degrees of motion are also possible, such as angular tilt in any
direction, freely movable in space; however such further degrees of freedom are likely to be largely
limited in practice by the constrained surgical environment in which the surgical instrument 100 is
being used. A combination of all these motions enables a high level of flexibility to be accomplished
with this surgical instrument 100, with added advantage of better control as movement is distantly
dictated by surgeon's hand. Further details of the operational characteristics of the surgical
instrument 100 and specialized instrument architecture designed to achieve the same are given
hereinbelow in Figures 1-8, and associated description.
In various embodiments, the carriage plate assembly 20 cooperatively engages with the proximal end
5(a) of the elongated shaft 10 that extends along the shaft axis 12 and includes an actuating system
25 that may be fixedly held therein by suitable fastening arrangements for ease of assembly. The
elongated shaft 10 includes an outer shaft casing that forms substantially a hollow conduit. The outer
shaft casing has a proximal end 5(a) that is rotatably coupled to the carriage plate assembly 10 and
an open distal end 5(b) to engage the wrist member 30 and pair of working members 40(a) and
40(b). The instrument 100 is typically releasably mounted to a robotic arm by means of an
interfacing member. To be suitable for minimally invasive surgery the surgical instrument must be
operable about axis that intersect at the orifice through which the instrument is inserted into the
patient.
It is to be appreciated that the field of application of the invention is not limited to surgical
procedures at internal surgical sites only, but can be used on open surgical sites as well.
Re-referring to Figure 1, a disassembled view of the surgical instrument 100 is presented that
includes a unique and novel transmission or actuation system, all housed within the carriage plate 20
to facilitate different motions of the instrument 100 required to perform surgical procedures
including roll motion of the shaft 10 about the shaft axis 12, wrist-like motion of the wrist member
30 about the wrist axis, and scissor like motion of the working members 40(a) and 40(b) about the
working member axis, wherein the working members can be displaced angularly about the working
member axis independently of the other, so that the working members, together as a whole 40, is
angularly displaceable.
As best can be seen in Figure 1 in combination with Figure 2, it will be appreciated that the wrist
member 30 is coupled to the distal end 5(b) of the shaft 10 by a pivotal connection to define a wrist
axis 32 about which the wrist member 30 exhibits wrist like motion as it gets angularly displaced in
either direction. Likewise, the working members 40(a) and 40(b) are pivotally mounted to the
opposed working end of the wrist member 30 to pivot about the working member axis defining a
scissor like arrangement. It will be appreciated that the working members 40 can be in the form of
any required surgical tool having two members or fingers which pivot about a common pivotal axis,
such as scissors, pliers for use as needle drivers, any electrocautery instruments or the like.
The wrist member axis 32 remains non parallel, and substantially perpendicular to the shaft axis 12
thereby permitting wrist member 30 to rotate relative to the shaft axis 12 around two substantially
orthogonal axis. Likewise the wrist member axis 32 and the working member axis also remain non
parallel, and substantially orthogonal to each other. It has to be noted that the free ends of the
working members 40 are angularly displaceable about the working member axis 32 towards and
away from each other in a scissor-like fashion, independently of each other, such that the working
member 40 as a whole is displaceable in either direction.
Referring to Figure 3 and also to Figure 2, the wrist member axis 32 have disposed thereupon a
pulley means 36 defining a circumferentially extending channel to wound thereon a wrist-member
moving elongate element 38 that extends towards the proximal end 5(a) of the shaft 10, as described
in greater detail now. As can be seen in Figure 3, the pulley means 36 includes a centrally disposed
hole through which the pivotal pin 34 extends to establish a pivotal connection of the wrist member
30 with the elongated shaft 10. With reference to Figure 3, the working member axis is flanked by
two set of pulleys 44 and 46 which are coaxially positioned on the pivotal connection 42 to be
generally co-planar relative to each other.
Similar to the pulley means 36 of the wrist member 30, each pulley 44 and 46 defines a
circumferentially extending channel to receive the respective working member-moving elongate
elements 48 and 50 that extends towards the proximal end 5(b) of the shaft 10. The working
member-moving elongate elements 48 and 50 snugly pass through a slot provided on the wrist
member 30 before they join with wrist-member moving elongate element 38 in their travel through
the hollow conduit of shaft 10 towards its proximal end 5(a).
Reference is now made to Figure 4-8, according to a further preferred embodiment, the inside view
of carriage plate 20 showing a preferred arrangement of actuating system 25 and elongate elements
for generating movements needed for the instrument to function, is presented. As can be clearly seen
in Figure 4, the carriage plate assembly 20 has been compartmentalized by two upright support
members 62 and 82 extending upwardly from horizontally laid carriage plate 20 to apparently form
three compartments therein.
The first compartment 60 of the carriage plate 20 is separated from second compartment 70 by a
support column 62 held in an upright position perpendicular to the carriage plate 20. The first
compartment 60 is configured to engage a gear assembly 64, shown in Figure 8, as will be discussed
in greater detail below. Such gear assembly 64 operably couples with the elongated shaft 10 to
permit rotation of the shaft about the shaft axis 12. More specifically and with reference to Figure 8,
the gear assembly 64 includes a stack assembly of three gears 64(a), 64(b) and 64(c), preferably spur
gears having gear ratio of at least 1:1, being configured to meshingly engage with each other and
rotate in unison to generate desired power for shaft rotation. Though, a single gear may also replace
the present embodiment of three gears in gear assembly 64, it will however occupy larger workspace
and will deviate from the idea of conserving space within the carriage plate 20, much desired to
make the instrument independently movable relative thereto.
Referring to Figure 4 & 5, and as was discussed above, the support column 62 defining boundaries
of first compartment 60, includes vertically spaced openings 62(a), 62(b) and 62(c), wherein opening
62(a) is configured to receive shaft rotating actuator 25(a) that axially extends therethrough and
operably cooperates with the gear assembly 64 to result in rotational movement of the surgical
instrument 100 about the shaft axis 12. The opening 62(b) engages with a support shaft 66, generally
provided to support the central gear 64(b) of the stack gear assembly (shown in Figure 8), and the
opening 62(c) sized and shaped to receive the elongated shaft 10.
Referencing to Figure 4 -8, one form of actuation system 25 within the carriage plate 20 includes a
bracket plate 72 adapted for fixed securance to the second compartment 70 defined in the carriage
plate 20, to support the actuating system 25. The actuating system 25 comprising plurality of
actuators, particularly the shaft actuating actuator 25(a), at least two wrist member-moving actuators
25(b), 25 (c), first working member-moving actuator 25(d) and second working member-moving
actuator 25(e) that extends through plurality of spaced apart slots 74(a), 74(b), 74(c), 74(d), 74(e)
provided on the bracket plate 72 that are sized to receive actuators 25 of suitable proportion and
dimensions.
As depicted in Figure 8, in one specific, but not limiting embodiment, the shaft rotating actuator
25(a) extending axially through top-most opening 62(a) of the support column 62 advances through
the slot 74(a), the two wrist member-moving actuators 25(b) and 25(c) advances through 74(b) and
74(c) and first working member-moving actuator 25(d) and second working member-moving
actuator 25(e) advances respectively through slots 74(d) and 74(e). One of skill in the art will
recognize that plurality of actuators 25 advancing through given slots on the bracket plate 72 shall
not be construed limiting in sense that any actuator may be allowed to advance through any slot
depending on the pattern in which one desires to lay the network of elongate elements. Further
combinations of above embodiment may be gleaned by person skilled in art, and hence is not
discussed separately in the present disclosure.
As previously described, the second compartment 70 is separated from the third compartment 80 by
a second uprightly extending support column 82. As can be seen in Figure 4-7, the support column
82 includes two spaced apart openings to receive respectively the two wrist member-moving
actuators 25(b) and 25(c) protruding from the bracket plate 72. In one embodiment, the support
column 82 further defines towards its peripherals a pair of arcuate slots to receive respectively the
first working member-moving actuator 25(d) and second working member-moving actuator 25(e),
also protruding from afore-mentioned bracket plate 72. However, those ordinary skills in the art will
appreciate that the support column 82 can be designed like any other support column including
spaced apart openings to receive and hence support actuator assembly such that requisite space is
conserved for each actuator for free actuated motion, thus also allowing instrument to be of
minimum size and weight.
Turning to Figure 4 and 5 again, a preferably raised platform raised right angularly from the carriage
plate 20 and well-suited for supporting and securing an urging arrangement 76 and a channeling
structure 78 is presented. Such an urging arrangement 76 comprises a pair of spaced apart composite
pulley assemblies 76(a) and 76(b), each assembly further comprising a set of three idler pulleys-
76(a;), 76(a ), 76(aui) and 76(bi), 76(b ), 76(biu) (not individually marked and shown in Figure)
arranged in a stacked fashion such that bottommost pulleys of each set 7 (a and 76(bm) are secured
fixedly to the platform, engaging thereupon central pulleys 76(a ) and 76(bu), that further bears
securely thereupon topmost idler pulleys 76(a;) and 76(b;). The channeling structure 78 hereinfore
mentioned includes a first guide pulley 78(a) and second guide pulley 78(b) maintained in a suitably
oriented plane, but different, preferably lower, from that of the urging arrangement 76. It has to be
noted that the set of idler pulleys are provided further with a pair of ball bearings.
As can be seen in Figure 5, the third compartment 80 of the carriage plate 20 comprises a pair of
oppositely disposed side columns 84(a) & 84(b), disposed in generally vertically upstanding relation
in respect to the carriage plate 20, and inclined at surface facing towards each other so as to mount
upon the inclined surface a first guiding mechanism 86 comprising a pair of guide pulleys 86(a) and
86(b) that are positioned at a requisite angle with respect to shaft axis 12. Preferably, the angles are
maintained between 30 degrees to 65 degrees relative to centrally extending shaft axis 12. These
idler pulleys are provided with ball bearings as above.
As is further depicted in Figure 5, an L-shaped raised platform is provided in the third compartment
80 to support the second guiding mechanism 88 comprising a set of idler pulleys 88(a) and 88(b)
supported with a pair of ball bearings, each set further comprising a set of at least two pulleys 88(a;),
88(a ), 88(b ) and 88(b ) (not individually shown in Figure) laid in a stacked configuration. The r
shaped configuration the platform positions one set of idler pulley in a plane higher than the other
for the reasons as illustrated in greater detail now.
As indicated above, the working member-moving elongate elements 48 and 50 along with wristmember
moving elongate element 38 travel through the hollow conduit of shaft 10 towards its
proximal end 5(a). Thus, each elongate element forming two sides of each single continuous
elongate element as 38(a), 38(b), 48(a), 48(b), 50(a) and 50(b), and totaling to six travels the length
of shaft 10 that extends up to the second compartment 70. Now, six elongate elements entering the
second compartment 70 of carriage plate 20 are urged through the urging arrangement 76 so that the
elongate elements remain closer to each other, and hence the shaft axis 12. In one embodiment, the
elongate elements are kept at a distance of not more than 1.4mm from each other.
As shown in Figure 6, the first working member moving elongate element 48 engaging pulley means
44 at the working member axis at distal end, returns along the length of shaft 10 and urged through
the urging arrangement 76 to engage topmost idler pulley 76(a;) with its one end 48(a), while the
other end 48(b) engages the bottommost pulley 76 ¾) of second composite pulley assembly 76(b).
Likewise, the second working member moving elongate element 50 engages another pulley means
46 coaxially positioned at the working member axis, returns along the length of shaft 10 and urged
through the urging arrangement 76 to engage topmost idler pulley 76(b;) with its one end 50(a),
while the other end 50(b) engages the bottommost pulley 7 6(a of first composite pulley assembly
76(a).
The wrist member-moving elongate element 38, on the other hand rides over the pulley means 36
disposed at the wrist member axis 32, over its circumferential channel, gets pulled backwards to run
through the shaft 10, urge through the urging arrangement 76 to engage its two free ends 38(a) and
38(b) with central idler pulleys 76(a ) and 76(b ) respectively.
Now, as clearly shown in Figure 6, the wrist member-moving elongate elements 38(a) and 38(b)
then snugly travels towards the third compartment 80 where it wounds, at least partially around the
guide pulleys 86(a) and 86(b) respectively before it gets anchored to wrist member moving actuators
25(b) and 25(c) respectively that controls rotation of the wrist member 30 about wrist axis 32 as
shown in Figure 7.
The actuators, in one preferred embodiment, are configured to include an elongated shaft 10 that is
capable of mounting thereupon a multi-grooved pulley assembly fastened thereto by fastening
mechanism e.g. by means of a grub screw or other suitable fastener that securely affixes the pulley
assembly to the motor shaft. The multi-grooved pulley is further configured to receive the elongate
element that wraps around the pulley and is pretensioned to at least half of maximum operating
tension to eliminate any slack. The multi-grooved pulley, in one specific embodiment, includes on
its peripherals a pair of identical disks that also remains fastened to the motor shaft by any suitable
fastening mechanism. One of the disks of the two identical disks, preferably the one positioned
outwardly towards the end of motor shaft, is a split disk that includes two semi-circular portions
interlocked with each other by a fastening means to form a complete aperture disk. The upper semicircular
portion is typically a C-type pulley that is adapted to effectuate pretensioning of cable
engaging therewith. The elongate element is pretensioned, up to a maximum of half the yield
strength of the elongate element, to a level that avoids any segment thereof going slack at peak
applied torque and avoids backlash.
In one significant aspect of the invention, the elongate element wounds around the multi-grooved
pulley and is configured to slip through one opening and extend out from another opening provided
on the multi-grooved pulley, following which in order to inhibit stretching of the elongate element
along its length, an elongate relatively rigid member e.g. hypotube portions are introduced at the end
of the elongate element extending out through the opening. The hypotube portions are then typically
crimped in the ends to automatically lock the elongate member in the tensioned configuration. The
hypotube is typically hollow tube having a cross-sectionally circular profile. Once the free end of
elongate element is crimped, the C-type pulley is loosened slightly and counter-rotated to achieve
pretensioning of the elongate element to a desired pulley.
In one preferred embodiment, on each side of the multi-grooved pulley assembly, a bearing 23,
preferably ball bearing, rides on the actuator shaft secured thereto, and held therein by a mounting
plate to prevent radial play of the pulley while the motor is in actuated state. Thus, referring to
Figure 6 & 7, the wrist member moving elongate elements 38(a), 38(b) wounds around respective
multi-grooved pulleys 25(b ), 25(Cj) (not shown in Figure), with the ends of elongate elements
configured to slip through openings on the multi-grooved pulleys 25(b ), 25(q) and extend out to be
introduced with hypotube portions and get pretensioned. This involves two identical disks around the
peripherals of multi-grooved pulleys, 25(b ), 25(biu) and 25(c ), 25( ) with one of the pulleys being
a C-type pulley (as explained above) - 25(biu), 25( ) to pretension the elongate elements. The multigrooved
pulleys 25(b ), 25(Cj) further held by mounting plates 28(b), 28(c) and supported by pair of
bearings 23(b;), 23(bu) and 23(c;), 23(c ) .
In accordance with the mode of anchoring the elongate element to respective actuator, the free ends
of wrist member moving elongate element 38(a) and 38(b) are guided through respective guide
pulleys 86(a) and 86(b) to get snugly secured to respective actuators 25(b) and 25(c). Again, these
guide pulleys are provided with ball bearings.
As indicated above, the free end of first working member moving elongate element 48(a) upon being
partially guided by the topmost idler pulley of the urging arrangement 76(a;) extends towards the
proximal end of the carriage plate 20 to engage idler pulley 88(ai) of the second guiding mechanism
88 before getting anchored to the respective multi-grooved pulley 25(d;) [25(d ), 25(diu)] of the first
elongate member moving actuator 25(d) that protrudes up to the third compartment. At the actuator
25(d), the elongate element gets pretensioned in a manner discussed above involving C-type pulley
25(diii), mounting plate 28(d) and bearings 23(d;) and 23(d ) .
In like manner, the other free end of the first working member moving elongate element 48(b) upon
being partially guided by the bottommost idler pulley 76(b i) of second composite pulley of the
urging arrangement gets routed through an outer periphery of the second guide pulley 78(b) of the
channeling structure 78 and advances into the third compartment to engage bottommost idler pulley
88 (a ) of the second guiding mechanism 88.
Now, the first end 48(a) and the second end 48(b) of the first working member moving elongate
element gets anchored to the first working member-moving actuator 25(d) and gets pretensioned and
secured thereto in a manner explained above.
In a similar fashion, the first free end of second working member moving elongate element 50(a)
upon being partially guided by the topmost idler pulley of the urging arrangement 76(bi) extends
towards the proximal end of the carriage plate 20 to engage top laid idler pulley 88(bi) of the second
guiding mechanism 88 before getting anchored to the respective multi-grooved pulley 25(e [25(e ),
25(eui)] of the second elongate member moving actuator 25(e) that protrudes up to the third
compartment 80. At the actuator 25(e), the elongate element gets pretensioned in a manner discussed
above by involving C-type pulley 25(eui), mounting plate 28(e) and bearings 23(e;) and 23(¾).
Now, the other free end of the second working member moving elongate element 50(b) upon being
partially guided by the bottommost idler pulley 76(aui) of first composite pulley of the urging
arrangement gets routed through an outer periphery of the first guide pulley 78(a) of the channeling
structure 78 and advances into the third compartment to engage bottommost idler pulley 88 ) of
the second guiding mechanism 88.
Thus, the first end 50(a) and the second end 50(b) of the second working member moving elongate
element gets anchored to the second working member-moving actuator 25(e) and gets pretensioned
and secured thereto in a manner explained above.
In one preferred embodiment of the present invention, the elongated elements are partially formed of
a length of flexible cable and atleast one hypotube portion that gets secured to one end of the flexible
cable. Care should however be taken to prevent over-rotation of the instrument which would cause
the cables to twist into contact with each other and create friction between the cables. In one other
significant aspect of the invention, the actuators are sterlizable.
As is also depicted in Figure 6, the ends of first and second working member moving elongate
elements 48(a), 48(b), 50(a) and 50(b) arrange themselves in a decussate configuration such that
minimal space yet maintaining a minimal separation from each other to prevent criss-crossing of
elongate elements as they travel from urging arrangement towards their respective actuators. The
distance between the elongate elements is maintained preferably, not less than 1mm. From the given
arrangement of elongate elements, it will be appreciated by those skilled in the art that the first and
second working members are displaceable between open and close positions by decussate
arrangement of elongate elements, in a scissor like fashion while the working members are biased
towards the closed position.
Included in the concept of this invention are various modifications of the operable coupling between
the actuating system 25, guiding mechanisms 78, 88 and elongate elements 38, 48 and 50 that can
provide requisite actuation motions to the instrument, and will be apparent to those of ordinary
skilled in the art. Therefore, it has to be understood that the specific engagements and combinations
illustrated in given embodiments of the disclosure constitute only few possible embodiments for the
purposes of explanation, and the invention is not meant to be limited by any particular combination.
Each actuator 25(a), 25(b), 25(c), 25(d) and 25(e) further includes magnetic encoders 31(a), 31(b),
31(c), 31(d) and 31(e) to enable motion control as they create close loop for motion that helps define
trajectory of actuators to reset motion of the working members 48 & 50, as shown in Figure 8.
Further the carriage plate 20 supports printed circuit boards 33(a), 33(b), 33(c), 33(d) and 33(e) that
is operably coupled to end of actuators 25(a), 25(b), 25(c), 25(d) and 25(e), and is further another
printed circuit board is supported by the carriage plate 20 for energizing the actuators.
In at least embodiment, the surgical instrument, allows selective movement of the wrist member, the
first and second working members by selective pulling of the corresponding elongate element in
response to control signals applied thereto. The ends of each actuator are held by pulley holding
plate that houses one of the bearings that secures the pulley.
Now referring to Figure 9, surgical instrument 100 having replaceable working members that allows
substituting a more appropriate tip for a previous one for performing the same function, or for
performing a different function relative to the wrist member 30 onto which the working members
40(a) and 40(b) are mounted, is presented. The newly replaced working members assure accurate
positioning of the working tip and effect easy replacement or substitution of working members
relative to the wrist member 30. The proposed mechanism enables all working members 40(a) and
40(b) of same or similar type to bear same working relationship with respect to wrist member 30,
thus maintaining its working axis preferably orthogonal to wrist member axis.
In one illustrated embodiment of the surgical instrument 100 including a disposable or replaceable
working members 40(a) and 40(b), allows close coupling or attachment of the working members
with the wrist member 30, which for the purposes of explaining the effect of replacement of working
member tips, shall be referred to as the receptacle over which the working members rest. The
disposable or replaceable working members 40(a) and 40(b) may be used for cutting, shearing,
grasping, engaging, or contacting tissue adjacent a surgical site.
In one general aspect, embodiments of the present invention provide a surgical instrument having
replaceable working members that can control the lifetime of the surgical instrument more
accurately.
As discussed previously in the description, particularly in Figure 2 & 3, the working member axis,
positioned orthogonally to wrist member axis 32 in space, is flanked by two set of pulleys 44 and 46
which are coaxially positioned on the pivotal connection 42 to be generally co-planar relative to each
other. However, preferably as shown in Figure 9 and 10, the replaceable working member 40 is
bipolar cautery instrument, wherein each working member is independently and removably coupled
with respective pulley means, working member 40(a) with pulley means 46 and working member
40(b) with pulley means 44. While Figure 9 depicts the working members 40 fixedly coupled with
the respective pulley means, Figure 10 is an exploded view that briefly explains the mechanism of
coupling the pulley means with respective working members.
To enable an independent removable coupling, each pulley means 44 and 46 is designed to include
respectively a relatively first square-like protrusion or block 54, 56 having disposed thereupon at
least one relatively circular opening 52(a), 52(b) exhibiting an abutting relationship with adjacent
pulley means 44, 46 respectively. The opening is sized to receive the elongate element 48, 50
unitarily with the pulley means 44 and 46 as shown in Figure 10.
Again as seen in Figure 10, the square-like protrusion or block 54, 56 includes second square -like
protrusion which may be either a disengageable unit or may be integrally formed with square-like
block 54, 56. For the purposes of illustration only, and by no means to restrict the scope of present
disclosure, the first square-like block and the second square-like block are construed to be formed
integrally with second square-like block being of size and dimensions relatively smaller than the first
block 54, 56.
While the first-square like block 54, 56 further defines a slot 54(a), 56(a) toward its exterior surface,
as shown in Figure 10, the second-square like block also defines a slot 54(b), 56(b) towards its
exterior surface such that an engaging member 58 (a), 58(b) engages respectively the working
member 40(a), 40(b) respectively with the pulley means 44 and 46. The second-square like block
towards its end configured to engage with the working member defines an opening homogeneous
with an opening provided at the coupling end of the working member such that the two opening are
securely interconnected and are fixedly held therein by a suitable engaging member 58(a), 58(b).
The engaging member 58(a), 58(b), in one preferred embodiment is a flat or round stainless steel
wire whose one free end is pushed through slot 54(a), 56(a) on the first-square like protrusion/block
54, 56 from exterior portion towards the interior, and reverse pulled through another slot 54(b), 56(b)
provided on second-square like protrusion so as to tighten the stretch or span of wire. In other
alternate arrangement, other flexible material exhibiting properties of high tensile strength and
corrosion resistance.
A complementary arrangement, as indicated above, provided towards the coupling end of working
member 40(a) and 40(b) includes a complementary opening of size and dimension that can fittedly
engage with the slot 54(b), 56(b), such that the two attaching components now define a common
unitary slot 54(b), 56(b) that receives the other end of engaging member, as defined above.
The two free ends of each engaging member, emerging towards the exterior, are now bundled or
banded by applying a strapping material, a flexible material most commonly steel or plastic so as to
ensure a tight fit. The straps, commonly designated as 59, and individually as 59 (a) and 59(b) for
working members 40(a) and 40(b) respectively, are locked conventionally by a lock which forms an
integral part thereof. The engaging member 58 is preferably formed to have a rough, abrasive
surface, at least towards its ends that gets bundled by the straps 59 to prevent slithering away of
engaging member from locking strapping material.
Alternatively, in one other embodiment, the ends of engaging member 58(a), 58(b), may be pulled
tightly and crimped by a portion of hypotube in a manner discussed in previous sections of the given
detailed description.
In one other preferred embodiment, the inner surface of working members 40(a), 40(b) that shoulder
each other during closing of the surgical instrument 100, is cut towards its coupling end in a receding
flat surface to form an arcuate slot such that the engaging members 58(a), 58(b) running
therethrough the slots 54(b), 56(b) respectively do not create any gap therebetween the working
members in the closed position of the surgical instrument due to its thickness. The engaging member
thus rests within the receding portion or the arcuate slot of the inwardly facing surface of the
working member and never interferes with the closing and opening mechanism of the surgical
instrument by pushing itself therebetween the tips of working members.
Referring now to Figure 11, the second-square like block of each working member 40(a), 40(b) on
its side walls houses a steel ball 47, and within its housing accommodates a spring arrangement 49.
The spring arrangement 49, in general, comprises one or more spring element or any other suitably
selected resilient element that gets pressed or compressed when the working member is made to
establish a snap-fit connection with the pulley means housing a slot. The coupling end of working
member includes an opening that rides over the second-square like block and hence the steel balls
47, compresses the spring or resilient element 49 and snap-fit the components together in a secure
linkage.
The foregoing description has been directed to one or more specific embodiments of the surgical
instrument. It will be apparent; however, that other variations and modifications may be made to the
described embodiments, with the attainment of some or all of their advantages. Accordingly this
description is to be taken only by way of example and not to otherwise limit the scope of the
invention, or depart from the basic inventive concepts. All such variations and modifications are to
be considered within the scope of the present invention, the nature of which is to be determined from
the foregoing description and the appended claims.
What is claimed is:
A surgical instrument comprising:
a longitudinal shaft having shaft axis defining a proximal end and a distal end, said
shaft configured to be rotatable about the shaft axis;
a wrist member coupled to the distal end of the shaft by a pivotal connection defining a
wrist axis, said wrist member being angularly displaceable about the wrist axis by
atleast two wrist member-moving actuators operatively coupled to a single continuous
wrist member-moving elongate element such that selective pulling of one end of the
elongate element causes concomitant movement of the wrist member therewith in one
direction while counter-pulling causes movement of the wrist member in opposed other
direction; and
a first working member and a second working member coupled by a common pivotal
connection to working end of the wrist member to define working member axis, and
configured to be displaced angularly about the working member axis when
independently actuated respectively by first working member-moving actuator coupled
with corresponding first working member-moving elongate element or second working
member-moving actuator coupled with corresponding second working member-moving
elongate element.
The surgical instrument of claim 1, wherein the wrist axis is substantially perpendicular to shaft
axis thereby permitting the wrist member to rotate relative to the shaft axis around two
substantially orthogonal axis.
The surgical instrument of claim 1, wherein the wrist axis and the working member axis are
substantially orthogonal to each other.
The surgical instrument of claim 1, wherein the elongate elements are formed partially of a
length of flexible cable and atleast one hypotube portion secured to one end portion of the
flexible cable, said elongate elements extending from the wrist member, first working member
and second working member towards the proximal end of the shaft.
The surgical instrument of claim 1, further comprising an actuator to permit rotation of the shaft
about shaft axis.
6) The surgical instrument of claim 1, further comprising a carriage plate adapted to releasably
secure the surgical instrument with a robotic arm of a minimally invasive surgical system.
7) The surgical instrument of claim 1, wherein the carriage plate being cooperatively engaged with
the proximal end of the shaft houses the atleast two wrist member-moving actuators, the first
working member-moving actuator, the second working member-moving actuator and the shaft
rotating actuator.
8) The surgical instrument of claim 7 , wherein the actuators housed within the carriage plate are
sterlizable.
9) The surgical instrument of claim 6, the carriage plate further comprising an urging arrangement
arranged to urge the elongate elements coming out of the shaft towards each other by a
predetermined amount to keep them closer to the shaft axis.
10) The surgical instrument of claim 9, wherein the predetermined amount corresponds to a
distance not more than 1.4mm.
11) The surgical instrument of claim 9, wherein the urging arrangement comprises at least two
composite pulley assemblies, each composite pulley assembly further comprising a stack of at
least three idler pulleys, wherein topmost idler pulleys of the stacks are configured to receive
first end of the first working member elongate element and the second working member elongate
element respectively; the central idler pulleys are configured to receive one end each of the wrist
member moving elongate element; and the bottommost idler pulleys being configured to receive
second end of the working member elongate elements such that second working member
elongate element is received by the bottommost idler pulley of the stack whose topmost idler
pulley receives the first end of first working member elongate element and second end of first
working member elongate element is received by the bottommost idler pulley of the stack whose
topmost idler pulley receives the first end of second working member elongate element.
12) The surgical instrument of claim 1, wherein the first working member and the second working
member are configured to be displaceable between open and close position in a scissor like
fashion relative to each other, said working members being biased towards the closed position.
13) The surgical instrument of claim 1, wherein the wrist member-moving elongate element is
adapted to wound around diametrical portion of a pulley means disposed at the wrist member,
wherein free ends of the elongate element extend through the shaft towards its proximal end, are
urged through the urging arrangement so as to be routed over a first guiding mechanism before
getting anchored to respective wrist member-moving actuators.
14) The surgical instrument of claim 13, wherein the first guiding mechanism includes a pair of
guide- pulleys mounted at a requisite angle with respect to the shaft axis in a manner capable of
receiving one end each of the wrist member-moving elongate element and routing it towards
respective wrist member-moving actuator.
15) The surgical instrument of claim 14, wherein the guide-pulleys are inclined at an angle
preferably between 30 degrees to 65 degrees relative to the shaft axis.
16) The surgical instrument of claim 13, wherein each of the wrist member-moving actuator
comprises an elongated actuator shaft mounting thereupon an multi-grooved pulley assembly
fastened thereto by a fastening mechanism, the multi-grooved pulley configured to receive wrist
member-moving elongate element that is pretensioned to at least half of maximum operating
tension to eliminate any slack.
17) The surgical instrument of claim 16, wherein the multi-grooved pulley includes on its
peripherals a pair of identical disks fastened to the actuator shaft, wherein at least one of the disk
is a split disk including two-semi-circular portions with at least one of the two semi-circular
portions being designed to effectuate pretensioning of the wrist member-moving elongate
element, the two semi-circular projections then forming a complete aperture disk.
18) The surgical instrument of claim 16, the multi-grooved pulley receiving the wrist membermoving
elongate element have disposed thereupon one or more spaced holes being sized to
receive the elongate element, said elongate element being further adapted to receive a hypotube
that remains at least partially compressed to automatically lock the elongated element in a
tensioned configuration.
19) The surgical instrument of claim 17, wherein the semi-circular disk portion effectuating
pretensioning is slightly loosened and counter-rotated to pretension the entire wrist membermoving
elongate element to a desired level.
20) The surgical instrument of claim 16, wherein the actuator shaft is further mounted thereupon
with at least one bearing on either side of multi-grooved pulley to reduce radial play of said
multi-grooved pulley assembly.
21) The surgical instrument of claim 1, wherein at least two pulley means are coaxially positioned
and disposed at working member axis to wound at least partially, around their diametrical
portions, the first working member-moving element and second working member-moving
element respectively, wherein free ends of each of the elongate elements extend through the
shaft towards its proximal end and are urged through the urging arrangement.
22) The surgical instrument of claim 21, wherein first end of the first working member-moving
element wounds at least partially around the topmost idler pulley of the first composite pulley
assembly of the urging arrangement and extends towards proximal end of the carriage plate to be
guided over a second guiding mechanism before getting anchored to the first working membermoving
actuator.
23) The surgical instrument of claim 21, wherein second end of the first working member-moving
element wounds at least partially around bottommost idler pulley of the second composite pulley
assembly of the urging arrangement, gets routed through an outer periphery of a second guide
pulley that forms part of a channeling structure, is further guided by the second guiding
mechanism before getting anchored to the first working member-moving actuator.
24) The surgical instrument of claim 20, wherein first end of the second working member-moving
element wounds at least partially around the topmost idler pulley of second composite pulley
assembly of the urging arrangement and extends towards proximal end of the carriage plate to be
guided by a second guiding mechanism before getting anchored to the second working membermoving
actuator.
25) The surgical instrument of claim 20, wherein second end of the second working membermoving
element wounds at least partially around bottommost idler pulley of the first composite
pulley assembly of the urging arrangement, gets routed through an outer periphery of first guide
pulley that forms part of the channeling structure, is further guided by the second guiding
mechanism before getting anchored to the second working member-moving actuator.
26) The surgical instrument of claim 23, wherein the second guiding mechanism includes a set of
idler pulleys aligned in a stacked configuration so as to allow top laid idler pulleys of each set
receive respectively the first end of the first working member-moving elongate element and the
second working member-moving element, and the bottom laid pulleys receive alternate second
ends of working member moving elongate elements such that second end of first working
member moving element is received by the bottom laid idler pulley of the stack whose top laid
idler pulley receives the first end of second working member-moving elongate element, and
second end of the second working member moving element is received by the bottom laid idler
pulley of the stack whose top laid idler pulley receives the first end of first working membermoving
elongate element .
27) The surgical instrument of claim 26, wherein the first working member-moving elongate
element received by the top laid idler pulleys is maintained in a different plane from that of
second working member-moving elongate element received by the second set of idler pulleys,
such that ends of each of the first working member-moving elongate elements and second
working member-moving elongate elements arrange in a decussate configuration, yet
maintaining a minimal separation to eliminate frictional engagement therebetween, as they
effectuate scissor like motion of the working members relative to each other.
28) The surgical instrument of claim 23, wherein the channeling structure is constituted of the first
guide pulley and the second guide pulley maintained in a plane other than that of the urging
arrangement, so configured to channelize the second ends of each of the second working
member-moving elongate element and first working member-moving elongate element through
their outer periphery respectively, to prevent criss-crossing of elongated elements as they extend
towards the proximal end of carriage plate.
29) The surgical instrument of claim 1, wherein each of the first working member and second
working member moving actuators comprise an elongated actuator shaft mounting thereupon a
multi-grooved pulley assembly fastened thereto by a fastening mechanism, the multi-grooved
pulley configured to receive respectively, the first working member-moving elongate elements
and the second working member-moving elongate elements, said elongate elements being
pretensioned to at least half of maximum operating tensions to eliminate any slack.
30) The surgical instrument of claim 29, wherein the multi-grooved pulley includes on its
peripherals identical disks fastened to the working member-moving actuator shaft, wherein at
least one of the disk is a split disk including two-semi-circular portions with at least one of the
two semi-circular portions being designed to effectuate pretensioning of the working membermoving
elongate element, the two semi-circular projections then forming a complete aperture
disk.
31) The surgical instrument of claim 29, the multi-grooved pulley receiving the working membermoving
elongate element have disposed thereupon one or more spaced holes being sized to
receive the elongate element, said elongate element being adapted further to receive a hypotube
that remains at least partially compressed to automatically lock the elongate element in a
tensioned configuration.
32) The surgical instrument of claim 30, wherein the semi-circular disk portions of the two
respective working member-moving actuators effectuating pretensioning are slightly loosened
and counter-rotated such that each of the working member-moving elongate element gets
pretensioned to a desired level.
33) The surgical instrument of claim 30, wherein the actuator shaft of each of the working
member-moving actuator is further mounted thereupon with at least one bearing to reduce radial
play of the multi-grooved pulley.
34) The surgical instrument of claim 1, wherein the carriage plate further houses an actuator
drivingly engaged with a gear assembly to permit rotation of the shaft about the shaft axis.
35) The surgical instrument of claim 34, wherein the gear assembly comprises two or more gears
arranged in a stack configuration such that desired power is achieved by operable engagement of
the gear assembly configuration with the actuator to permit rotation of the shaft.
36) The surgical instrument of claim 34, wherein the gear assembly includes plurality of gear,
preferably spur gears having gear ratio of 1:1.
37) The surgical instrument of claim 7, wherein the actuators are further coupled to magnetic
encoders to enable motion control as it creates close loop for motion that helps define trajectory
of actuators to reset motion of the working members.
AMENDED CLAIMS
received by the International Bureau on 22.1 1.2014
s claimed is:
A surgical instrument comprising:
a longitudinal shaft having shaft axis defining a proximal end and a distal end, said
shaft configured to be rotatable about the shaft axis;
a wrist member coupled to the distal end of the shaft by a pivotal connection defining a
wrist axis, said wrist member being angularly displaceable about the wrist axis by
atleast two wrist member-moving actuators operatively coupled to a single continuous
wrist member-moving elongate element such that selective pulling of one end of the
elongate element causes concomitant movement of the wrist member therewith in one
direction while counter-pulling causes movement of the wrist member in opposed other
direction; and
a first working member and a second working member coupled by a common pivotal
connection to working end of the wrist member to define working member axis, and
configured to be displaced angularly about the working member axis when
independently actuated respectively by first working member-moving actuator coupled
with corresponding first working member-moving elongate element or second working
member-moving actuator coupled with corresponding second working member-moving
elongate element.
The surgical instrument of claim 1, wherein the wrist axis is substantially perpendicular to shaft
axis thereby permitting the wrist member to rotate relative to the shaft axis around two
substantially orthogonal axis.
The surgical instrument of claim 1, wherein the wrist axis and the working member axis are
substantially orthogonal to each other.
The surgical instrument of claim 1, wherein the elongate elements are formed partially of a
length of flexible cable and atleast one hypotube portion secured to one end portion of the
flexible cable, said elongate elements extending from the wrist member, first working member
and second working member towards the proximal end of the shaft.
The surgical instrument of claim 1, further comprising an actuator to permit rotation of the shaft
about shaft axis.
6) The surgical instrument of claim 1, further comprising a carriage plate adapted to releasably
secure the surgical instrument with a robotic arm of a minimally invasive surgical system.
7) The surgical instrument of claim 1, wherein the carriage plate being cooperatively engaged with
the proximal end of the shaft houses the atleast two wrist member-moving actuators, the first
working member-moving actuator, the second working member-moving actuator and the shaft
rotating actuator.
8) The surgical instrument of claim 7 , wherein the actuators housed within the carriage plate are
sterlizable.
9) The surgical instrument of claim 6, the carriage plate further comprising an urging arrangement
arranged to urge the elongate elements coming out of the shaft towards each other by a
predetermined amount to keep them closer to the shaft axis.
10) The surgical instrument of claim 9, wherein the predetermined amount corresponds to a distance
not more than 1.4mm.
11) The surgical instrument of claim 9, wherein the urging arrangement comprises at least two
composite pulley assemblies, each composite pulley assembly further comprising a stack of at
least three idler pulleys, wherein topmost idler pulleys of the stacks are configured to receive
first end of the first working member elongate element and the second working member elongate
element respectively; the central idler pulleys are configured to receive one end each of the wrist
member moving elongate element; and the bottommost idler pulleys being configured to receive
second end of the working member elongate elements such that second working member
elongate element is received by the bottommost idler pulley of the stack whose topmost idler
pulley receives the first end of first working member elongate element and second end of first
working member elongate element is received by the bottommost idler pulley of the stack whose
topmost idler pulley receives the first end of second working member elongate element.
12) The surgical instrument of claim 1, wherein the first working member and the second working
member are configured to be displaceable between open and close position in a scissor like
fashion relative to each other, said working members being biased towards the closed position.
13) The surgical instrument of claim 1, wherein the wrist member-moving elongate element is
adapted to wound around diametrical portion of a pulley means disposed at the wrist member,
wherein free ends of the elongate element extend through the shaft towards its proximal end, are
urged through the urging arrangement so as to be routed over a first guiding mechanism before
getting anchored to respective wrist member-moving actuators.
14) The surgical instrument of claim 13, wherein the first guiding mechanism includes a pair of
guide- pulleys mounted at a requisite angle with respect to the shaft axis in a manner capable of
receiving one end each of the wrist member-moving elongate element and routing it towards
respective wrist member-moving actuator.
15) The surgical instrument of claim 14, wherein the guide-pulleys are inclined at an angle
preferably between 30 degrees to 65 degrees relative to the shaft axis.
16) The surgical instrument of claim 13, wherein each of the wrist member-moving actuator
comprises an elongated actuator shaft mounting thereupon an multi-grooved pulley assembly
fastened thereto by a fastening mechanism, the multi-grooved pulley configured to receive wrist
member-moving elongate element that is pretensioned to at least half of maximum operating
tension to eliminate any slack.
17) The surgical instrument of claim 16, wherein the multi-grooved pulley includes on its
peripherals a pair of identical disks fastened to the actuator shaft, wherein at least one of the disk
is a split disk including two-semi-circular portions with at least one of the two semi-circular
portions being designed to effectuate pretensioning of the wrist member-moving elongate
element, the two semi-circular projections then forming a complete aperture disk.
18) The surgical instrument of claim 16, the multi-grooved pulley receiving the wrist membermoving
elongate element have disposed thereupon one or more spaced holes being sized to
receive the elongate element, said elongate element being further adapted to receive a hypotube
that remains at least partially compressed to automatically lock the elongated element in a
tensioned configuration.
19) The surgical instrument of claim 17, wherein the semi-circular disk portion effectuating
pretensioning is slightly loosened and counter-rotated to pretension the entire wrist membermoving
elongate element to a desired level.
20) The surgical instrument of claim 16, wherein the actuator shaft is further mounted thereupon
with at least one bearing on either side of multi-grooved pulley to reduce radial play of said
multi-grooved pulley assembly.
21) The surgical instrument of claim 1, wherein at least two pulley means are coaxially positioned
and disposed at working member axis to wound at least partially, around their diametrical
portions, the first working member-moving element and second working member-moving
element respectively, wherein free ends of each of the elongate elements extend through the
shaft towards its proximal end and are urged through the urging arrangement.
22) The surgical instrument of claim 21, wherein first end of the first working member-moving
element wounds at least partially around the topmost idler pulley of the first composite pulley
assembly of the urging arrangement and extends towards proximal end of the carriage plate to be
guided over a second guiding mechanism before getting anchored to the first working membermoving
actuator.
23) The surgical instrument of claim 21, wherein second end of the first working member-moving
element wounds at least partially around bottommost idler pulley of the second composite pulley
assembly of the urging arrangement, gets routed through an outer periphery of a second guide
pulley that forms part of a channeling structure, is further guided by the second guiding
mechanism before getting anchored to the first working member-moving actuator.
24) The surgical instrument of claim 20, wherein first end of the second working member-moving
element wounds at least partially around the topmost idler pulley of second composite pulley
assembly of the urging arrangement and extends towards proximal end of the carriage plate to be
guided by a second guiding mechanism before getting anchored to the second working membermoving
actuator.
25) The surgical instrument of claim 20, wherein second end of the second working member-moving
element wounds at least partially around bottommost idler pulley of the first composite pulley
assembly of the urging arrangement, gets routed through an outer periphery of first guide pulley
that forms part of the channeling structure, is further guided by the second guiding mechanism
before getting anchored to the second working member-moving actuator.
26) The surgical instrument of claim 23, wherein the second guiding mechanism includes a set of
idler pulleys aligned in a stacked configuration so as to allow top laid idler pulleys of each set
receive respectively the first end of the first working member-moving elongate element and the
second working member-moving element, and the bottom laid pulleys receive alternate second
ends of working member moving elongate elements such that second end of first working
member moving element is received by the bottom laid idler pulley of the stack whose top laid
idler pulley receives the first end of second working member-moving elongate element, and
second end of the second working member moving element is received by the bottom laid idler
pulley of the stack whose top laid idler pulley receives the first end of first working membermoving
elongate element .
27) The surgical instrument of claim 26, wherein the first working member-moving elongate
element received by the top laid idler pulleys is maintained in a different plane from that of
second working member-moving elongate element received by the second set of idler pulleys,
such that ends of each of the first working member-moving elongate elements and second
working member-moving elongate elements arrange in a decussate configuration, yet
maintaining a minimal separation to eliminate frictional engagement therebetween, as they
effectuate scissor like motion of the working members relative to each other.
28) The surgical instrument of claim 23, wherein the channeling structure is constituted of the first
guide pulley and the second guide pulley maintained in a plane other than that of the urging
arrangement, so configured to channelize the second ends of each of the second working
member-moving elongate element and first working member-moving elongate element through
their outer periphery respectively, to prevent criss-crossing of elongated elements as they extend
towards the proximal end of carriage plate.
29) The surgical instrument of claim 1, wherein each of the first working member and second
working member moving actuators comprise an elongated actuator shaft mounting thereupon a
multi-grooved pulley assembly fastened thereto by a fastening mechanism, the multi-grooved
pulley configured to receive respectively, the first working member-moving elongate elements
and the second working member-moving elongate elements, said elongate elements being
pretensioned to at least half of maximum operating tensions to eliminate any slack.
30) The surgical instrument of claim 29, wherein the multi-grooved pulley includes on its
peripherals identical disks fastened to the working member-moving actuator shaft, wherein at
least one of the disk is a split disk including two-semi-circular portions with at least one of the
two semi-circular portions being designed to effectuate pretensioning of the working membermoving
elongate element, the two semi-circular projections then forming a complete aperture
disk.
31) The surgical instrument of claim 29, the multi-grooved pulley receiving the working membermoving
elongate element have disposed thereupon one or more spaced holes being sized to
receive the elongate element, said elongate element being adapted further to receive a hypotube
that remains at least partially compressed to automatically lock the elongate element in a
tensioned configuration.
32) The surgical instrument of claim 30, wherein the semi-circular disk portions of the two
respective working member-moving actuators effectuating pretensioning are slightly loosened
and counter-rotated such that each of the working member-moving elongate element gets
pretensioned to a desired level.
33) The surgical instrument of claim 30, wherein the actuator shaft of each of the working membermoving
actuator is further mounted thereupon with at least one bearing to reduce radial play of
the multi-grooved pulley.
34) The surgical instrument of claim 1, wherein the carriage plate further houses an actuator
drivingly engaged with a gear assembly to permit rotation of the shaft about the shaft axis.
35) The surgical instrument of claim 34, wherein the gear assembly comprises two or more gears
arranged in a stack configuration such that desired power is achieved by operable engagement of
the gear assembly configuration with the actuator to permit rotation of the shaft.
36) The surgical instrument of claim 34, wherein the gear assembly includes plurality of gear,
preferably spur gears having gear ratio of 1:1.
37) The surgical instrument of claim 7, wherein the actuators are further coupled to magnetic
encoders to enable motion control as it creates close loop for motion that helps define trajectory
of actuators to reset motion of the working members.
38) A surgical instrument comprising:
a longitudinal shaft having shaft axis defining a proximal end and a distal end;
a wrist member coupled to the distal end of the shaft by a pivotal connection defining a
wrist axis; and
a first working member and a second working member replaceably coupled by a common
pivotal connection to working end of the wrist member to define working member axis.
39) The surgical instrument of claim 38, wherein the wrist axis and the working member axis are
substantially orthogonal to each other.
40) The surgical instrument of claim 38, wherein the first working member and the second working
member are configured to be displaceable between open and close position in a scissor like
fashion relative to each other, said working members being biased towards the closed position.
41) The surgical instrument of claim 38, wherein at least two pulley means are coaxially positioned
and disposed at working member axis to wound at least partially, around their diametrical
portions respective working member moving elongate element.
42) The surgical instrument of claim 41, wherein each pulley means is adaptable to include at least
first protruding block having disposed thereupon an opening defining an abutting relationship
with the pulley means so as to receive the elongate element unitarily therethrough and said
pulley means.
43) The surgical instrument of claim 42, wherein the first protruding block has further disposed
thereupon a first slot, and further accommodates thereupon a second protruding block, optionally
integrally formed therewith, to provision defining of a second slot.
44) The surgical instrument of claim 38, wherein the first and the second working member, towards
its end coupleable with the respective pulley means, have a complementary arrangement
including an opening sized to interconnect securely with the second protruding block of the
pulley means and define a unilateral second slot along with the second protruding block.
45) The surgical instrument of claim 38, wherein the pulley means is securely locked with the
respective working member by means of an engaging member that is pushed through the first
slot disposed on the first protruding block, and then reverse pulled through the second slot
defined unilaterally by the second protruding block and the respective working member.
The surgical instrument of claim 45, wherein the engaging means includes a stainless steel
or any other flexible material having high tensile strength.
47) The surgical instrument of claim 45, wherein the engaging means extending through the first and
subsequently the second slot towards exterior, defines its two free ends that are strapped using a
suitable strapping material to securely lock the coupling between working member and the
respective pulley means.
48) The surgical instrument of claim 45, wherein the engaging member has at least in portion,
particularly towards its end that engages with the strapping material has rugged abrasive surface
to prevent slithering away of engaging member from locking strapping material.
49) The surgical instrument of claim 38, wherein the first and second working member towards their
end to be coupled with respective pulley means, is cut into an arcuate slot such that the engaging
member running therethrough rests comfortably within the arcuate slot and do not intervene with
movement of working members towards or away from each other.
50) The surgical instrument of claim 43, wherein the second protruding block houses a steel ball and
spring arrangement that enables snap fit of the working member with the pulley means in a
secure linkage.